Method of and apparatus for measuring distance



H. C. HAYES A April 16, 1929.

METHOD OF AND APPARATUS FOR MEASURING DISTANCE Filed Jan. 31. 1922 2 Sheets-Sheet Inventor Harvey C. Hayes Attorney METHOD OF AND APPARATUS FOR MEASURING DISTANCE Filed Jan. 31. 1922 2 Sheets-Sheet 2 Harvey C. Hayes Patented Apr. 16, 1929.

UNITED STATES r AT HARVEY C. HAYES, OF ANNAPOLIS, MARYLAND.

METHOD OF AND APPARATUS FOR MEASURING DISTANCE Application filed January 31, 1922. Serial No. 533,092.

My invention relates generally toa method of and apparatus for measuring distance, and more particularly to determining distance by measuring the time of sound traverse between two points.

An object of my invention is to determine with a high degree of accuracy the time'of sound traverse between a sound source and a sound receiver.

Another object is to provide a device that is simple and reliable in operation, cheap to manufacture, and having a marked degree of efliciency.

With these and other objects in view the invention consists in the construction, .combination, and arrangement of parts so as to utilize certain characteristics of-sound as will be hereinafter described.

Reference is to be had to the accompanying drawings forming part of this specification in which like reference characters indicate corresponding parts throughout the several by measuring the time required for a sound signal to travel between the two points.

My method of sound ranging is especially applicable to the determination of the distance from a'sound source to a reflecting or echo producing surface, as by employing the echo, the source and the receiver can be located at the same station and the measurement of the time interval thus simplified and error reduced, as the time interval to be measured is doubled.

It has been found that most submarine surfaces, such as are furnished by rocks, ledges, precipitous coasts, icebergs and all kinds of sea bottom, are eflicient reflectors of submarine sounds. Also because of the low viscosity, homogeneity, and relatively slow movement of sea water, it transmits sounds to great distances and with but slight bending or change of direction. a V

My method of sound ranging might be widely used as an aid and safeguard to navigation by enabling the navigator to take soundings as well as to determine the distance of his vessel from rocks, ledges, precipitous coasts, and icebergs. This is possible because of the simplicity with which the device may be operatedon ship board by the ships personnel.

It has been found that if arrangements are made so that of two sounds one stimulates one ear and the other stimulates the other ear then the simultaneity of the two can be judged to within from 1/200th to 1/1000th of a second-if two sounds are unlikethe accuracy of judgment depending upon the character and sharpness of the two sounds, but depending relatively little on theobserver. If the two sounds are alike, as are sound and its echo, then the simultaneity can be judged to within 1/100,000th of a second. This phenomenon is due to the operation of the binaural sense.

Referring more particularly to Figure 1 of the drawings, 5 represents a motor adjustable to give and hold a desired speed, which drives a gear 6 mounted on a shaft 7. The drive mechanism between the motor and gear is not shown, as it may be of any conventional or desired construction and arrangement. Ballbearings 9, arranged on the upper'side of a pedestal 8 in which the shaft-7 is mounted, support the gear 6. Tothe free end of the shaft I fixedly secure, by any desired means, i

a disk 10, and housings 11 and 12 interposed between the gear and disk additionally support the latter.

A frame 13 has a bar '14, a'portion of whose upper surface is cut away, asat 15, to provide stops 16 and 17 at either end, secured between its uprights as at 18 and 19. Between thev stops I slidably mount a carriage 20 having a U shaped member 21fintegrally formed thereon, the cross bar of which is provided with a rack 22. One of the end bars of this U- shaped member has secured thereto a pointer H 23 which is movable along a scale 24 secured to the cross bar 25 of'the frame 13. Stopping blocks 26 secured within the carriage are adapted to engage with the stops 16 and 17 to limit the movement thereof. A cylinder 27 rotatably surrounds the carriage 20 and is supported therefrom by ball-bearings 28 mounted in bearings 29 carried by both the cylinder and carriage. One end of the cylinder is enlarged and has a ring 30, preferably of fibre, fitted in a groove 31 and engaging with the disk 10 whereby motion is imparted to the cylinder. Extending longitudinally of the cylinder there is a triangular-shaped recess 32, having its larger end the more remote from the enlarged cylinder head.

To .vary the speed of the cylinder by moving it radially inward or outward along the disk I use a pinion gear 33 meshing with the rack 22, the gear being operable through a thumb knob 34.

The mechanism operating an oscillatory circuit, illustrated in Fig. 5, connected to the binding posts 35 and 38, consists of a breaker arm 36, rider wheel 37, stationary arm 39, and contact 40. The arm 36 is electrically connected with the binding post 38 and is resiliently connected to an insulating block 41 by a screw 42 or other suitable means, while the arm 39 is electrically connected with the binding post 35 through the stud 43 which passes through a suitable insulated housing 44 mounted within the cross bar 25. The contacts are normally held open by the rider wheel, but are closed for an instant during each revolution of the cylinder when the wheel drops into the recess. It will thus be observed that the oscillatory circuit is closed for an instant every time the cylinder revolves, and since the speed of the cylinder can be varied uniformly the interval between signals can be given any value between certain limits, but as the larger end-pf the recess is towards the center of the disk, where rapid movement is imparted to the cylinder, the length of the signal remains approximately constant. A signal, having a constant or regulable duration, wholly. independent of changes in signal periodicity, is highly advantageous in permitting an absolute coin cidence in point of time, between echo and primary impulses when'the latter are com binded in a common receptive means, such as I have disclosed. It is apparent, that the triangular-shaped recess, constitutes a simple expedient for'limiting the length of signal to a definite time duration when cylinder 27,

in being adjusted for echo-signal coincidence, has been moved towardthe center of disk 10, its angular velocity being decreased, which; in the. absence of a recess having tapered width, would cause contacts 39 and 40 to remain closed for an indefinitely long period.

Fig. 5 shows one arrangement of the oscillating circuit and the receiver. A source of-alternating current 45, having preferably a frequency to give a musical note, supplies I sound receiver.

a winding on the core 48 which is permanently magnetized by a source of direct current 47. The fitld set-up acts on the diaphragm 49 in contact with water, as for instance being set in the skin 50 of a ship, causing it to vibrate when the circuit is closed through contact 40 (Fig. 3). One ear piece 510f'a telephone set 53 is coupled to the oscillating circuit through an adjustable coupling 46, the other ear piece 52 being in circuit .with a microphone detector 55, arranged to receive incoming wave energy from the water.

The operation of my invention is as follows:

The local signal is brought to one ear piece of a two telephone headset by an inductive connection between a receiver circuit and the I oscillatory circuit, operated by the contact 40. The other receiver is actuated by the echo of the signal received on a submarine The listener now adjusts the carriage 20 and cylinder 27 along the disk 10 by the thumb knob 34 until the signal and echo arrive at the two ears simultaneously; that is, the echo of a signal already made arrives at the same time as the next succeeding signal; or it would be possible to have the echo arrive at the same time as the second or third succeeding signal in which case the time of travel of the sound would be two or three times that of one revolution ofjthe cylinder. The time interval or period, if the scale is calibrated in such unit, may be readofi' directly by means of the pointer 23 which moves over the scale 24, or the scale'may be calibrated directly in fathoms, yards, or any other desired unit.

While the foregoing description takes care of sound ranging where an echo from the signals can be had, the" apparatus can be made suitable for observations where no echo is available. For instance, in Fig. 5 the line connecting the microphone 55 with the ear piece 52 may be a long line connecting two widely separated points, the distance between which is known, thus giving a means for measuring velocity. Since the velocity of the electrical effects in the circuit will be extremely high, the time of return of the signal from the distant microphone to the ear piece will be negligiblefor all practical pur-.

such as determining velocity of sound, if the range is known.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of my invention and that various minor changes in details of construction, proportion, and arrangement of parts may be made within the scope of the appended claims and without sacrificing any of the advantages of my invention.

Having fully described my invention, what I desire to secure by Letters Patent is 1. Apparatus for sound ranging comprising means for imparting a succession of sound signals to a homogeneous medium to produce echoes from an object the range of which is being measured, means for stimulating one ear of an observer with said signals the same instant they occur, means for stimulating the second ear of said observer with the echoes of said signals, means for adjusting the periodicity of said succession of signals,

' means for maintaining the duration of signal constant irrespective of changes in periodicity and means for translating said periv 2 odicity into a measure of range.

2. pparatus for determining the time measure of sound propagation over distance comprising meansfor generating a succession .of sound signals, means for stimulating one ear of an observer with said signals at the same instant they occur, means for receiving said signals after propagation over distance, means for stimulating the secondear of said observer with the signals the same instant they are received, and a plurality of means for adjusting and determining the eriodicity of said succession of signals inclu ing apparatus for rendering the duration of signal independent of variations in periodicity.

3. In a sonic distance measuring device including an electrically operated sonic transmitter, the combination with the transmitter of a rotating disc, means for rotating the disc at a constant angular speed, a carriage, means for supporting said carriage and rendering the latter radially adjustable over the disc, :1. revolvable member mounted on the carriage and having a portion of its periphery in contact with the face of the disc and means carried by the member for-making and breaking the electrical circuit of the transmitter,

4. In a sonic distance measuring device including an electrically operated sonic transmitter, the combination with the transmitter of a rotating disc, means for rotating the disc at a constant angular speed, a frame adjacent the disc, a support mounted upon the frame above the disc and parallel to its surface, a carriage slidable across the face of the disc and non-rotatably mounted upon the support, means for sliding the carriage along the support, means for adjusting the carriage to any point along the support and means mounted upon the carriage and contacting with the surface of the disc for making and breaking the electrical circuit of the sonic transmitter for a definite period of time irrespective of the position of the carriage along the support.

5. In a sonic distance measuring device ineluding an electrically operated sonic transresponsive compressional wave transmitter mitter, the combination with the transmitter pf a rotating disc, means for rotating the disc at a constant angular speed, a frame around said disc, a support carried by the frame, a carriage slidably mounted upon the support, the carriage having a rack thereon, a cylinder revolvably mounted on thecarriage and-engaging the surface of the disc, means carried by the cylinder for making and breaking the electrical circuit of the transmitter and means engaging with the rack for moving the carriage along the support.

6. In a sonic distance measuring device including an electrically operated sonic transmitter, the combination with the transmitter of a rotating disc, means for rotating the disc at a constant angular speed, revolvable means engaging the disc and movable thereover to vary the speed of the revolvable means, the revolvable means being provided with a recess extending longitudinally thereof, a plurality of contact arms, and means carried by one of the contact arms engaging the revolvable means for opening and closing the contact arms as they pass over the recess in the revolvable means, said recess being so proportioned that the duration of the signal is constant irrespective of the speed of rotation of the revolvable means.

7. In a-sonic distance measuring device including a sonic transmitter, the combination in the transmitter of a rotating disc, means for rotating the disc at a constant angular speed, electrical means for creating sound signals, an electric circuit therefor, a carriage, means for supporting said carriage and adapted to permit radial movement thereof with respect to the disc, means mounted on the carr'age and engaging the surface of the disc to e rotated thereby, said means being provided with a recess, means co-operating with said recess to periodically make and break said electric circuit, said means and recess being formed to provide a signal of constant duration by said make and break action, and means for moving the carriage radially with respect to the disc to regulate the time interval between sound signals.

8. In adepth measuring device an electroand manually adjustable means for impressing on said transmitter current impulses of constant length and variable periodicity.

9. In a distance measuring device an electro-responsive compressional wave transmitter, means for impressing periodic current impulses on said transmitter and adj ustable means for varying the periodicity of said impulses independently of the duration of said impulses.

10. In a distancemeasuring device an electro-responsive compressional wave transmitter, means for impressing periodic current impulses on said transmitter, and adjustable means, including an element rotatable at vari- 130 able speeds, for varying the periodicity of means for varying the periodicity of said'imsaid impulses independently of the duration pulses independently of the duration of said of said impulses. impulses, said means being adjustable to pro- 10 11. Ina distance measuring device, an elecvide variations of any magnitude Within a 5 tro-responsive compressional Wave transgiven range.

mitter, means for impressing periodic current impulses on said transmitter, and adjustable HARVEY C. HAYES. 

